Science in China Series D: Earth Sciences

, Volume 48, Issue 9, pp 1470–1478 | Cite as

Processes and environmental significance of the subglacial chemical deposits in Tianshan Mountains



On the bedrock surface of Glacier No.1 in the headwater of Urumqi River, Tianshan Mts., well layered and crystallized subglacial calcite precipitations were discovered. Based on observations and analysis of the surface form, sedimentary texture and structure, and chemical composition of the deposits, clues about the subglacial processes and environment are educed. The radial-growth crustation texture of the deposits, which builds up in the saturated CaCO3 solution, proves the existence of pressure melting water and water films under Glacier No.1; and their rhythmic beddings, dissolved planes and unconformable contacts show that the water films responsible for the formation of these structures were in a wide range of spatial as well as temporal variations. Though formed under continental glacier in non-limestone area, the deposits are quite similar to those formed under temperate glaciers in limestone areas, a fact that shows a similar process of chemical precipitation between the two. Hence the enrichment of calcium in the subglacial melting water and the process of precipitation have actually little to do with the bedrock lithology and the glacier types. The cemented detritus in the deposits are rich in Fe and Al while depleted in K, Na and Si; also the included clay mineral consists mainly of illite, which reveals some weak chemical weathering under the continental glacier. The subglacial CaCO3 precipitates when plenty of Ca++melt into the subglacial melting water on a comparatively enclosed ice-bedrock interface under a high CO2 partial pressure, the forming of subglacial chemical deposits therefore offers unequivocal evidence for the ongoing of subglacial chemical reactions.


subglacial processes chemical deposits continental glacier 


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  1. 1.
    Aharon, P., Oxygen, carbon and U-series isotopes of aragonites from Vestfold Hills, Antarctica: Clues to geochemical processes in subglacial environments, Geochimica et Cosmochimica Acta, 1988, 52: 2321–2331.CrossRefGoogle Scholar
  2. 2.
    Ford, D. C., Fuller P. G., Drake J. J., Calcite precipitates at the soles of temperate glaciers, Nature, 1970, 226: 441–442.CrossRefGoogle Scholar
  3. 3.
    Hallet, B., Subglacial silica deposits, Nature, 1975, 254: 682–683.CrossRefGoogle Scholar
  4. 4.
    Hallet, B., Deposits formed by subglacial precipitation of CaCO3, Geol. Soc. Am. Bull., 1976, 87(7): 1003–1015.CrossRefGoogle Scholar
  5. 5.
    Hallet, B., Subglacial regelation water film, Journal of Glaciology, 1979, 23(89): 321–334.Google Scholar
  6. 6.
    Page, N. R., Subglacial limestone deposits in the Canadian Rocky Mountains, Nature, 1971, 229: 42–43.CrossRefGoogle Scholar
  7. 7.
    Souchez, R.A., Lemmens, M., Subglacial carbonate deposition: an isotopic study of a present-day case, Palaeogeography, Palaeocli- matology, Palaeoecology, 1985, 51: 357–364.CrossRefGoogle Scholar
  8. 8.
    Huang, M. H., Movement mechanism of sub-polar glaciers in China, Science in China, Series B, 1994, 24(3): 310–316.Google Scholar
  9. 9.
    Wang, Z. X., Song, G. H., Li, G., Observation and experiment on inner flow characteristics of Glacier No. 1 in the Urumqi River headwaters, Tianshan, investigation on artificial tunnel Part 1, 1985, Journal of Glaciology and Geocryology (in Chinese), 1985, 7(2): 123–131.Google Scholar
  10. 10.
    Cai, B. L., Huang, M. H., Xie, Z. C., A primary study of ice tem-perature to Glacier No.1 in the headwaters of Urumqi River, Tianshan, Chinese Science Bulletin (in Chinese), 1987, 32(22): 1732–1733.Google Scholar
  11. 11.
    Jing, Z. F., Surface velocity and the termini variations of Glacier No.1 at the headwater of Urumqi River, Tianshan, Annual Report of Tianshan Glaciological Station (in Chinese), 1999, 15: 154–159.Google Scholar
  12. 12.
    Feng, Z. G., Wang, S. J., Sun, C. G. et al., Practical index to dis-tinguish the origin of earthy deposits in karst area-characteristics of grain size distribution, Carsologica Sinica (in Chinese), 2002, 21(2): 73–78.Google Scholar
  13. 13.
    Li, X. H., Liu, Y., Tu, X. L. et al, Precise determination of chemi-cal composition in silicate rocks using ICP-AES and ICP-MS: a comparative study of sample digestion techniques of alkali fusion and acid dissolution, Geochimica (in Chinese), 2002, 31(3): 289–294.Google Scholar
  14. 14.
    Wang, Z. Y., Zhang, J. Q., Walf, W. C. et al., Atlas of the Sedi-mentary Textures and Structures (in Chinese), Beijing: Geological Publishing House, 1988: 71–72.Google Scholar
  15. 15.
    Weiss, R. F., Bucher, D., Oeschger, H. et al., Compositional varia-tions of gases in temperature glaciers, Earth and Planetary Science Letters, 1972, 16: 178–184.CrossRefGoogle Scholar
  16. 16.
    Engelhardt, W. V., The Origin of Sediments and Sedimentary Rocks, New York: John Wiley & Sons, 1977, 359.Google Scholar
  17. 17.
    Okitsugu, W., Nobuko, K., Yutaka, A. et al., A preliminary re-port on the chemical composition of glaciers in the Eastern Tian Shan Mountains, Journal of Glaciology and Geocryology, 1983, 5(3): 91–100.Google Scholar
  18. 18.
    Weertman, J., On the sliding of glaciers, Journal of Glaciology, 1957, 3: 33–38.Google Scholar
  19. 19.
    Weertman, J., The theory of glacier sliding, Journal of Glaciology, 1964, 5(39): 287–303.Google Scholar

Copyright information

© Science in China Press 2005

Authors and Affiliations

  • Gengnian Liu
    • 1
  • Risheng Luo
    • 1
  • Jun Cao
    • 1
  • Zhijiu Cui
    • 1
  1. 1.College of Environmental SciencesPeking UniversityBeijingChina

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